Three-phase motors which are often used in motor vehicles can be fully or partially operated electrically are controlled by means of a rectifier device, such as for example a frequency converter. In this case, a switching unit designed with semiconductor components typically forms half-bridge circuits with an output part. The latter is supplied by means of an intermediate circuit which in particular filters undesirable alternating currents occurring during the switching operations of the switching unit. It has been already proposed to use several filter elements, each provided with an intermediated circuit capacitance, in order to realize broadband filtering of these alternating current components. The purpose of the filter is in particular to prevent mutual interference between the high-voltage components in the motor vehicle to improve electromagnetic compatibility and to increase the lifespan of a battery connected with the rectifier device which is sensitive to alternating currents.
DE 100 62 075 A1 discloses an inverter which is connected to an intermediate voltage circuit provided with a charge storage device, wherein the convertor contains a semiconductor or bridge circuit, and the half-bridge or bridge circuit is a component of a unit arranged in a housing, wherein the charge storage device is provided with several intermediate circuit capacitors, among which one component, several of them, or all of them are also integrated components of the module.
DE 199 47 476 A1 discloses an inverter for converting electric energy for a network onboard a vehicle provided with a half-bridge, which comprises at least a high-side and a low-side switch equipped with a predefinable number of switches which are provided with a common connection that is connected to a means generating electric energy and to a capacitor connected in parallel to the half-bridge.
EP 2 608 389 A1 discloses a rectifier circuit comprising at least two submodules in a series circuit, which is related via an inductor to electric power supplied from a power source delivering a DC voltage. Each submodule is on the input side provided with a one-phase half-bridge and with a single-phase full-bridge on the output side, wherein the half-bridge, the full-bridge and an intermediate circuit capacitor are connected in parallel on the DC voltage side. Furthermore, a discharge circuit for discharging the intermediate circuit of the submodules is connected in parallel to the submodules that are connected in series and to the capacitor.